Non-specific Instruments: The instrument code in SEED format covers most commonly used instruments that generate time series. For instruments not specifically covered by an existing instrument code the Y instrument code can be used.

Instrument Code
Y

Orientation Code
Instrument Specific. Should be documented in the URL referenced below.

Further Usage:
In order to document the instrument type and provenance of the data, SEED header information must be available that documents the instrument that was used to generate the time series. A Channel Comment Blockette (059) must be provided in the SEED metadata. The Channel Comment Blockette should provide a short description of the instrument, the type of measurement it makes and provide a Uniform Resource Locator (URL) referencing the FDSN web site that fully describes the instrumentation. In addition to the requirement to include a B059, it is required to put a short description of the process/instrument in the 30 character channel comment (field 7 of B052).

X & Y Instrument Codes (pdf)